A major problem found with prior art probe inlet apparatus is the low atmosphere leakage that is experienced between the vacuum chamber and the adjacent environment, when the solid probe body is moved into and out of the vacuum chamber. Generally, probe insertion and withdrawal is performed manually, and therefore control and uniformity of the speed of the movements vary from operator to operator. Thus, the leakage problem becomes significant if the opening and sealing of the entry to the chamber does not occur in a synchronous manner with the probe movement. In such event, the vacuum is not maintained at a desired level and further probe analysis may be erroneous.